
NCE25 models that support an N2 Bus are always bus supervisors on the N2 Bus. They do not
require a user assigned device address to communicate on the N2 Bus.
Binary output source power selection jumpers
The BO source power selection jumpers determine whether a BO provides internal power (sourced
from the network engine) to the output load (INT position) or requires an external power source
(EXT position) for the output load. Figure 11 shows an example of the NCE controller BOs and the
associated power selection jumpers next to the BO terminal blocks.
Position the jumpers next to the BO terminals to provide either internal 24 VAC power to the BO
load or act as a switch for an externally powered BO. Each NCE25 BO wired in an application must
have the jumpers positioned properly for the application. See Figure 11.
Important:
Do not connect an external power source to a BO when the BO power source
jumper is in the internal power (INT) position. Connecting external power to a BO that sources
internal power can damage the controller and void any warranties.
Display screen and display navigation keypad
Specified NCE25 models feature an integral display screen and display navigation keypad. Use
these features to can view and edit the I/O points settings on the network engine. See Figure 3.
Refer to the
DIS1710 Local Controller Display Technical Bulletin (LIT-12011270)
for more information on
using the display screen and keypad.
Troubleshooting
LED status indicators
The NCE25 models have up to 11 LEDs (depending on model) to indicate power and network
communication status. Figure 16 shows the LEDs and Table 15 describes the LED indications.
Figure 16: NCE/NIE LED designations
LED test sequence at startup
During startup, the network engine automatically initiates an LED test to verify the operational
status of the LEDs. When you turn on the NCE, the following LED lighting sequence occurs:
1. The POWER, BATT FAULT, 10 LINK, FAULT, RUN, and PEER COM LEDs turn On, indicating that
the OS, is starting. (After 2 seconds, the LEDs may change states depending on the site-specific
NCE25 Installation Instructions
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